Substance abuse remains a prominent problem in the U.S. While the field of neuropharmacology has contributed substantially to the rapid advances in the science of addiction, the knowledge base required to design appropriate therapeutic modalities for substance abuse is incomplete. An obstacle to the continued progress of these efforts is the limited supply of creative, methodologically competent and dedicated scientists required to carry forward the effort into the 21st century. This request for continued funding of the Drug Abuse Training Program at the University of Texas Medical Branch capitalizes on a superb Program Faculty who exhibit multi-disciplinary research directions and methodological approaches that span from the examination of gene transcription to intracellular synaptic currents to the pharmacological analysis of drug discrimination mechanisms. The research directions of the Program Faculty extend over multiple neurotransmitters (e.g., excitatory/inhibitory amino acids, monoamines, acetylcholine) and neuro- modulators (e.g., CRF, opioids, hormones) and a multitude of methods, including molecular biology, electrophysiology, neurochemistry, and behavior. The present proposal is a request for continued funding of the Drug Abuse Training Program to educate pre- (N=2) and postdoctoral (N=2- 3) in the pharmacological and neural mechanisms of action of drugs of abuse for a period of 2-3 years. For predoctoral trainees, emphasis is initially placed upon imparting a rigorous academic background, an introduction to research concepts and methodologies via laboratory rotations followed by 2-3 years of original research on issues of primary importance to the elucidation of mechanisms by which drugs of abuse interact with neurotransmitters and influence neurotransmission. Postdoctoral trainees will concentrate on research throughout their training and will work closely with the Program Faculty who will facilitate the development of their scientific and professional careers. The present proposal draws upon the strengths of a multi-disciplinary faculty in pharmacology, toxicology and neuroscience to provide the scientific atmosphere in which students can develop an appreciation for the complex conceptual issues involved, the methodological approaches which can be applied, and the depth of the knowledge awaiting discovery. The only training grant on drug abuse in the expansive State of Texas is well positioned to generate a cadre of researchers dedicated to the study of substance abuse.